Simulated impacts of environmental parameters on tropical cyclone size and structure change

This project aims to improve basic understanding of the physical mechanisms associated with size and structure changes of a tropical cyclone due to interaction with its environment. Using the Weather Research and Forecasting (WRF) mesoscale model, the impacts of various changing environments, including vertical wind shear, atmospheric and oceanic temperature gradients, moisture, and other weather systems, on the size and structure (expansion/contraction) of the tropical cyclone are carefully investigated. Preliminary results indicate that there is a sensitivity in the tropical cyclone size (measured by the radius of gale-force winds) to both vertical wind shear strength and zonal direction with a larger, more intense tropical cyclone forming in easterly wind shear compared with westerly wind shear. In addition (not surprisingly perhaps), a larger and more intense tropical cyclone forms over warmer oceans for the same vertical wind shear. In the presentation, we will show these results plus those of sensitivities to temperature gradients, moisture, and equatorward-digging upper-level troughs.